This invention relates generally to projection screens. More specifically, the present invention relates to rear projection screens capable of use in a projection television (PTV) display arrangement.
Typical PTV display arrangements contain means for converting a video signal into an optical image. The optical image is projected upon a screen for viewing by an observer. In the case where the projection distance is relatively small, such as in compact PTV systems, the prior art arrangements are deficient.
Some prior art arrangements have an inherent lower optical efficiency near the outer edges of the screen or corner illumination problems, resulting in a "bright spot" in the center. Efficiency may be defined to be the ratio of the total amount of light which passes through the screen to the total amount of incident light received by the screen. Other prior art arrangements have attempted to improve the quality of the system by eliminating the bright spot effect. While these arrangements may have eliminated corner illumination problems, the overall efficiency of the screen and the contrast are reduced. Additionally, undesirable artifacts may be visible to the observer.